1. Field
The present disclosure is directed to semiconductor nanocrystal composites. More specifically, the semiconductor nanocrystal composites can protect semiconductor nanocrystals from degradation by radicals generated by a light source or external factors.
2. Description of the Related Art
A semiconductor nanocrystal, also referred to as a quantum dot (“QD”), is a crystalline semiconductor material having an average largest dimension, sometimes referred to herein as “average particle size”, of several nanometers (where nanoparticles are typically have a particle size of 1 nm to 100 nm, and a maximum particle size as high as several hundred nanometers), and composed of several hundred to several thousand atoms. A semiconductor nanocrystal has a large surface area per unit volume and exhibits various desirable electronic effects (e.g., quantum confinement) due to its small (e.g., several nanometers) average particle size. These structural characteristics and effects account for unique physicochemical properties of the semiconductor nanocrystal different from those found in bulk semiconductor materials of the same composition but with an average particle size greater than that of the semiconductor nanocrystal. For example, semiconductor nanocrystals absorb light from an excitation source to reach a higher energy excited state and emit energy corresponding to the energy band gap. Based on this principle, the energy band gap of semiconductor nanocrystals can be controlled by varying the size and/or composition of the semiconductor nanocrystals to produce light of various wavelengths from the semiconductor nanocrystals. Therefore, semiconductor nanocrystals find applications as luminescent materials in a variety of electronic devices, including display devices and bioluminescent display devices. Semiconductor nanocrystals free of toxic heavy metals such as lead and mercury possess many advantages as luminescent materials because of their environmental friendliness and safety in humans. Many techniques for controlling the size, structure and uniformity of semiconductor nanocrystals are currently being developed in order to utilize excellent characteristics and broad applicability of the semiconductor nanocrystals.
Semiconductor nanocrystals are currently employed for the fabrication of display devices and in other applications. The semiconductor nanocrystals may be used without any modification or in the form of composites in which the semiconductor nanocrystals are contained in a polymeric or inorganic matrix. However, the intrinsic characteristics of the semiconductor nanocrystals in these applications inevitably degrade during routine operation of the devices as well as by other external factors.